Cyril of Alexandria famously took up the debate against Nestorius on the theological interpretation of the deity of Christ, a number of which are addressed in these volumes. This fifth-century Christological controversey comprises most of the teaching of these letters, notably even letters not addressed to Nestorius. The conflict with Nestorius eventually brought Nestorius to condemnation after the Council of Ephesus in 431, in which Cyril presides at the request of Pope Celestine. Almost the entire collection here has to do with the controversey surrounding the Council of Ephesus and the schism of bishops on either side of the theological controversey.
